There was a sequence where it looked like the Frances character was making a Molotov cocktail. And then they showed her lurking outside Catherine's house the morning after Ann spent the night. And many references to Catherine not spending the night in the conservatory.
All leading me to believe that some night Catherine decided to sleep in her own room Frances would firebomb the place.
Was she found out before she had a chance to carry this out?
That bit was right after Tommy was urging Frances on, threatening to withdraw his attention if she didn't come up with anything extreme. Frances was previously quite content with just prodding Ryan forward in conversation.... I guess it was there to show the thought process of what was previously a decent, mild woman testing herself, "what would I be capable of?"
The late revelation of Tommy having 6 or 7 women visitors shows he was maybe looking for someone capable of going to extremes. Frances although looking at the flame, ultimately was not THAT kind of person.
Catherine's final conversation with Frances was spot on. You are not that type of person, go home and get on with your life.
Didn't get the impression that Frances wasn't 'that sort of person' I think she was willing to kill Catherine, but she saw that others might get hurt, including Ryan
I agree with this interpretation. She didn't do it because ultimately she was not a killer.
They introduced a brief red-herring with her stealing her sister's identity but then revealed the sister died of other causes and the sister's husband being chocked at Frances's behavior.
Frances was warped but she was another kind of victim as well, not just of Tommy but of other issues that made her drawn to him in the first place. I'd be curious to know what her own background was. No doubt some serious abuse issues back there.
I've been wondering if...in spite of Catherine's well-meaning attempts to reason with her...Frances will stay in town (she is out on bail after all) and still try to go through with the attack.